About the Analog Forecasting of Precipitation Objects (AnaPrO) Prototype Page
***This is an experimental product from WPC-DTB***

Overview

    Welcome to the WPC's Analog Forecasting of Precipitation Objects (AnaPrO) Prototype Page, which serves as an extension to the Tracking of Heavy Precipitation Objects (THePrO) Prototype Page. AnaPrO expands upon THePrO with providing displacement information for real-time objects by linking real-time objects to retrospective modeled objects and their observations. This displacement information is gathered for similar regions, intensities, time of year, and model forecast hours. More information is provided below.


Ensemble Details

    The WPC Ensemble QPF Tracking site is run for one CAM ensemble* shown below:


  • The HRRR is a Time Lagged Ensemble (TLE), but consists of only the extended runs (i.e. the runs that go out to forecast hour 48), which are performed every 6th hour. 

    •     * Additional ensembles will be added as suitable verification tracking archives are developed.

    Experimental Website Layout Part 1: HRRR Probabilities - Full CONUS

    Ensemble/Plot Type:

        The "HRRR Probabilities - Full CONUS" is the probability of an object centroid falling within 40 km of a point across all of CONUS. These probabilities are determined by linking similar retrospective objects to the current object. Similar objects are those objects within +/- 1 month, +/- 4 degrees of latitude and longitude, and +/- 12 hours lead time. Only objects that exist for 8 or more hours and can be linked to the retrospective archive are shown. Objects will appear to "vanish" as they propogate offshore because there there is no retrospective archive of similiar objects away from land.


    The images for "HRRR Probabilities - By Object" consist of the following:

        -- The blue shading represents the probability of an object centroid (that exists for 8 or more hours) occurring within 40 km of a point. This shading considers historical displacement biases in heavy precipitation objects and other anisotropic behaviors. 

    Threshold:
                ***currently there is only one threshold that is calculated***

    Initialization Model Time (Init):

            A drop down menu exists with all potential model initialization times.



    Experimental Website Layout Part 2: HRRR Probabilities - By Object

    Ensemble/Plot Type:

        The "HRRR Probabilities - By Object" is similar to the "HRRR Probabilities - Full CONUS" but focuses on one object at a time and includes object shape, centroid, and intensity details. Hence the toolbar changes when selecting "HRRR Probabilities - By Object" to include the ability to select each unique object, in addition to the "Plot," "Threshold," and "Init" selection options.


    The images for Centroid Probabilities consist of 4 attributes:

        -- The blue shading denotes the shape of the object (note all objects are plotted for this field).
        -- The object centroid path (black line) and marker color indicating the 90th percentile of hourly accumulated precipitation (left legend).
        -- Contour lines denoting the probability of object centroid location within 40 km of a point (also shown in "HRRR Probabilities - Full CONUS") given the retrospective object based verification. Note for the image below, the object typically verifies further east, but there is large spread, especially to the north. This verification is performed by comparing previously tracked model and observation objects.
        -- In the box to the northwest of the centroid, the probability that the observed object will exist (from the retrospective archive) for each model object. This is denotated as " P = " and then the probability.

    Object:

        For visual clarity, each object is plotted separately. Note that the probability of object centroid location is computed for each object separately and is based on the real-time object location, intensity, forecast hour, and time of year.

    Threshold:
        ***Currently there is only one threshold that is calculated***

    Initialization Model Time (Init):

        A drop down menu exists with all potential model initialization times.


    Experimental Website Layout Part 3: HRRR Centroid - Median Displacement

    Ensemble/Plot Type:

        "HRRR Centroid - Median Displacement" consists of ensemble plots from the HRRR-TLE mentioned above. Note that the toolbar changes when selecting "HRRR Centroid - Median Displacement" compared to "HRRR Probabilities - By Object", and consists of "Plot," "Threshold," and "Init" selection options.


    The images for Centroid Displacements consist of the following:

        -- The black line and marker symbol that indicates the QPF object centroid location and path, with the marker symbol denoting the model for some ensembles (right legend). 
        -- The marker color indicating the 90th percentile of hourly accumulated precipitation (left legend).
        -- The color scale on the right side of the product denoting the ensemble probability of being in a heavy precipitation object.
        -- The vector arrow for each real-time centroid denoting the median displacement (arrow length) and direction (arrow directon). Note that the tip of the arrow corresponds to the median location of the observed centroid objects (using a verification window) from the real-time modeled centroid.

    Threshold:
                ***currently there is only one threshold that is calculated***

    Initialization Model Time (Init):

            A drop down menu exists with all potential model initialization times.